I've seen solo/co-op variants for games like this (all vs. 1)... like there's a Last Night on Earth solo/co-op variant I wanna try where the zombies behave on a basic AI.

The Sin player doesn't really have a "turn", so I kind of feel like it would be easiest to give Sin an AI with its reactions. I've still not yet played my copy as I'm in the process of painting it, but I do a lot of solo-gaming too... I want to get a taste for what it's like to play against/as a real Sin player and then see if I can come up with a very simple set of rules the AI would follow.

But based on what I've seen in playthroughs and such, I'm tinkering with the idea that the AI would React with monster movement/attack if a player accomplishes something objective-driven and draw a random Sin reaction card if the player accomplishes anything at all (city action, kill a monster, rescue innocent, cleanse, etc.) but still keep the Sin's reaction token count.

The drawn card, if unable to play (like it's supposed to be played at start of Hero's turn, etc) would either be discarded and draw another or it would enter play and trigger at the first available opportunity... Meaning if Karl manages to kill an abomination, Sin reacts with start-of-turn card, the next hero would be affected rather than Karl.

Not sure how I like that since it breaks the flow of the Sin reacting to the CURRENT hero's actions.

But I definitely think it's possible to come up with a home-brew solo variant. We just have to put in the leg-work... I doubt CMON will do that for us.